This project concerns the physiological mechanisms of brain oscillations in the neocortex, a structure vital for perception, thought and memory. Brain oscillations are believed to be important for sensory processing, cognitive states such as attention, and for motor planning. Pathological alterations in brain oscillations have been shown to correlate with the existence of, and progression of, a variety of neuro-psychiatric conditions, including epilepsy, dementing disorders, and schizophrenia. Recent in vivo and in vitro data have demonstrated that a given cortical region can express, simultaneously, two different oscillations, produced (in the in vitro case) in different laminae. There are also numerous examples, in vivo, of oscillations of different frequency that are nested. Though considerable progress has been made in understanding the mechanisms underlying the generation of individual cortical rhythms, much less is known about multiple interacting neural rhythms seen in vivo and in vitro. The broad aims of this project are to examine, in further detail, the mechanisms of high-frequency brain oscillations, and to use that information as a platform for the study of spatiotemporal interactions of concurrently generated rhythms at the same, or at different, frequencies. We seek to understand how multiple oscillations may be co-expressed in single or interconnected networks, and how they may interact to facilitate cortical information processing. The specific aims of the project include the analysis of selected high-frequency rhythms (gamma (30-80 Hz) and synapse-dependent beta2 (20-80 Hz) rhythms generated in deep layers, very fast (>80 Hz) oscillations);the factors that determine when deep layers express gamma or beta2;the interactions of multiple rhythms within a single cortical column;the dynamics of multiple columns connected in an anatomically realistic manner. Techniques include both detailed and reduced network modeling. Better understanding of the cellular mechanisms of brain oscillations, and how oscillations become grouped together, could provide information as to whether "oscillation repair" is a reasonable clinical goal, in the sense that clinical interventions that normalize brain oscillations might also improve clinical symptoms. It may also help in the eventual use of brain oscillation signals as inputs to brain-machine-interface devices. PUBLIC HEALTH RELEVANCE This project concerns the physiological mechanisms of high frequency brain oscillations in the neocortex, a structure vital for perception, thought, and memory. Pathological alterations in these brain oscillations have been shown to correlate with the existence of, and progression of, a variety of neuropsychiatric conditions, including epilepsy, dementing disorders, and schizophrenia. Better understanding of the cellular mechanisms of brain oscillations, and how oscillations become grouped together, could provide information as to whether "oscillation repair" is a reasonable clinical goal, in the sense that clinical interventions that normalize brain oscillations might also improve clinical symptoms.